Two-year Skeletal Adaptations in Development and National Level Female Figure Skaters

Figure skaters typically have higher bone mineral density (BMD) than the general population. However, the current literature is limited to cross-sectional studies. The objective of this study was to determine two-year changes in volumetric BMD, bone microarchitecture, and estimated bone strength in elite national and development level Canadian figure skaters. Eleven female figure skaters aged 14+ years were recruited for this longitudinal study. Measurements occurred annually. High-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the radius and tibia underwent three-dimensional image registration. Total (Tt), cortical (Ct) and trabecular (Tb) volumetric BMD (mg HA/cm³), trabecular thickness (TbTh, mm) and cortical thickness (CtTh, mm) were determined. Finite element analysis estimated bone strength. Linear mixed effects models with subject random intercept and time×level interaction evaluated the influence of TtBMD over two-years. Eleven figure skaters completed baseline and one-year data collection, and nine completed the two-year study. All skaters were included in our models and were either national (n=5, 18.6-28.1 years) or development (n=6; 14.4-17.7 years) athletes. Significant time-by-level status (development or national) interactions indicated increases over time in development level athletes only for TtBMD, CtBMD, CtTh and bone strength at the radius and TtBMD, TbBMD, TbTh and bone strength at the tibia (p<0.01 for all). Bone outcomes did not change significantly over the two years in national level figure skaters. Changes in bone density, microarchitecture and strength were only observed in the younger, development level athletes. Given the differences in age between development and national level figure skaters, these results are understandable.